Cheap/recycled insulation?

[Number21]

I've got what is basically just a barn, with 2x4 walls and thin sheathing on the outside. That's it. Lots of big holes, the wind blows right through.

I want to close up all the holes, and cover the inside walls with OSB sheets, much like drywall. This alone will increase the insulation substantially, but what can I fill those walls with?

I don't want to spend much, and I don't really need a whole lot of R value. But anything is better than nothing. I thought about filling with packing peanuts but read it could be a fire hazard.

What else can I use that's cheap/free and recycled? Aluminum cans? Cardboard? (fire hazard?)

[DamonHD]

Have a look over at http://www.greenbuildingforum.co.uk/ for example.

I'd recommend against Al cans: lots of valuable embedded energy (they should be recycled) and inherently conductive.

What you choose will depend somewhat on how likely it is to get damp or wet.  If it might then sheets/lumps of expanded polystyrene might not be a bad plan, eg from discarded packaging.  Same stuff as the packing chips but unlikely to settle.  In a wooden barn I doubt it would be adding to any fire risk (though I am no expert).

If it won't get wet then you have many more opportunities, probably including all the stuff used to fill cavities in house walls.

Rgds

Damon